EEG Electrodes:
- Brain wave decoder EEG project step by step guide
- What is EEG and How it works
- What is the History of EEG waves and Neuro imaging techniques
- Brain computer interface BCI monitoring systems
- Functionality and Applications of the brain wave EEG project
- Material required for portable EEG system development
- How to select EEG electrodes for brain wave EEG project
- circuit designing steps for EEG portable monitoring device
- How to design filters for EEG circuit
- Schematic diagrams of brain wave EEG project
- Simulation analysis of brain wave controlling EEG project
- Challenges and Problems in EEG brain wave controlling project
- Final results of brain wave decoder EEG project
- How to filter EEG waves on MATLAB
- Future research for EEG project
- Hardware and software list for EEG project
01: Electrodes Selection
There are different types of EEG electrodes available. The passive and active electrodes available in the market. Signal picking is a challenging task in the development process. The low noise signal recording and for better skin contact for long time advance EEG electrodes installation is necessary.
The old and conventional methods used passive electrodes to measure brain signals. The shape of the electrodes is cup type and the material used is Ag-Agcl. There are different disadvantages in these conventional methods. Special and extra skin treatment and hair preparing needed for these methods.
In conventional methods the quality of signal is poor and very noisy signal. In the research for advance electrodes development the huge variety of electrodes and structures have been developed for better skin contact and low noise recording. The electrodes include conductive rubber, micro-tip electrodes, micro-machined, spring-loaded, bristle type of structures and the conductive foams. The Fig- shows the different types of methods of electrodes.
Electrode selection is the first part in the development of EEG system. As different types of EEG electrodes dry and non-dry electrodes available it was difficult to choose which method is good for our system.
For we have decoded to make our own electrodes from scratch. Low noise signal picking and electrodes designing was a challenging task. For electrodes designing there are different electrode materials available for good skin contact and conductivity. There are many issues involved in the designing process.
02: Our Design from scratch:
We have designed our own dry electrodes using sliver material, but the problem arises the electrodes are giving noise signal and the skin contact and gel issues making the system complex and little messy. The quality of signal was poor, so we have decided to use other electrodes. The Fig- shows our designed electrodes.
03: ECG Disposable Gel Electrodes:
These electrodes are easily available in the market. These electrodes are also used for capturing muscle activity the ECG and ECoG signal. So, these are easily available in medical stores. The response of these electrodes was good. The signal picking and skin contact was good, but the problem arises when the noise from wires added into the circuit. These electrodes come up with the special EEG wire structure.
We are using simple wires, so the noise was affecting the EEG signal. One more problem with these electrodes was these are not for long term for every new experiment we had to use new electrode, so this was not very suitable for a good and portable and long-term wearable system.
For getting low noise and quality signal, the electrodes should have good contact with the skin and good skin conductivity. These electrodes have good skin contact because of these come up with gel. The gel is used for better conductivity and capturing low amplitude EEG signal. There are dead cells on the skin surface so the dry electrodes without gel cannot capture EEG signal from the surface of the skin. The gel and skin preparation is necessary for getting the signal.
04: Gold Plated Dry Cup electrodes:
The final and mostly used method for getting EEG signal is to use cup electrodes. These electrodes have a disc and cup shaped with EEG noise reducing wires. That is the reason we have decoded to use these electrodes. These electrodes come up with EEG wires that cancel the noise and other artifacts for good EEG signal.
We can use the electrodes gel for better skin contact. These electrodes available in different materials like silver, gold plated, tin plated and other. The Gold have the good conductivity ratio among all other materials. So, we have decided to use the gold-plated electrodes.
These electrodes are not easily available in the market. As we have tested all other available and own made electrodes. All are not much suitable for our system. So, we have decided to order these electrodes. These are available on the online stores. We placed order online. These electrodes are easily available in china. The structure of the electrode is cup shape and they come up in different materials with the same size.
The main reason of ordering these electrodes is the wires used with these electrodes. There is a special wire for getting brain signal. In other wires the signal identification becomes more difficult because more noise added by other wires. These wires have the capability to remove the noise. Se we can move these wires they will not produce any noise to the system. We can use our system freely.
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